NASA is poised to launch its latest X-ray space telescope on a two-year hunt for hard-to-see objects lurking in the heart of the Milky Way and other galaxies.

The refrigerator-sized telescope was perched atop a rocket at a remote Pacific island launch site. On Wednesday, a carrier aircraft with the Pegasus XL rocket strapped underneath will take off from the Kwajalein Atoll, halfway between Hawaii and Australia. Upon its release, the rocket will free-fall for several seconds before igniting its engines for the climb into space.

The Nuclear Spectroscopic Telescope Array, or NuStar for short, focuses high-energy X-rays to peer through gas and dust in search of supermassive black holes in the center of galaxies, remnants of exploded stars and other exotic celestial objects.

While black holes are invisible, the region around them gives off telltale X-rays. NuStar will observe previously known black holes and map hidden ones. By exploring never-before-seen parts of the universe, scientists hope to better understand how galaxies form and evolve.

"We can view black holes and galaxies even if they're enshrouded with dust and gas. If you had high-energy X-ray eyes and you stared up out of the galaxy, what you would see is the glow of all the massive black holes sprinkled throughout the cosmos," chief scientist Fiona Harrison of the California Institute of Technology said this week.